Book Image

Essential Cryptography for JavaScript Developers

By : Alessandro Segala
Book Image

Essential Cryptography for JavaScript Developers

By: Alessandro Segala

Overview of this book

If you’re a software developer, this book will give you an introduction to cryptography, helping you understand how to make the most of it for your applications. The book contains extensive code samples in JavaScript, both for Node.js and for frontend apps running in a web browser, although the core concepts can be used by developers working with any programming language and framework. With a purely hands-on approach that is focused on sharing actionable knowledge, you’ll learn about the common categories of cryptographic operations that you can leverage in all apps you’re developing, including hashing, encryption with symmetric, asymmetric and hybrid ciphers, and digital signatures. You’ll learn when to use these operations and how to choose and implement the most popular algorithms to perform them, including SHA-2, Argon2, AES, ChaCha20-Poly1305, RSA, and Elliptic Curve Cryptography. Later, you’ll learn how to deal with password and key management. All code in this book is written in JavaScript and designed to run in Node.js or as part of frontend apps for web browsers. By the end of this book, you'll be able to build solutions that leverage cryptography to protect user privacy, offer better security against an expanding and more complex threat landscape, help meet data protection requirements, and unlock new opportunities.
Table of Contents (13 chapters)
Part 1 – Getting Started
Part 2 – Using Common Cryptographic Operations with Node.js
Part 3 – Cryptography in the Browser

Asymmetric and hybrid cryptography

In Chapter 5, Using Asymmetric and Hybrid Encryption in Node.js, we explained how asymmetric cryptography differs from symmetric (or shared key), and we looked at various examples of using asymmetric ciphers for encrypting data, performing key agreements, and building hybrid encryption schemes. In this section, we'll build upon what we learned in that chapter and show examples of using the same algorithms in a web browser, using the WebCrypto APIs.

Encrypting and decrypting short messages with RSA

RSA is the first asymmetric cipher we encountered in Chapter 5, Using Asymmetric and Hybrid Encryption in Node.js.

When using RSA, each party has a key pair consisting of a private key and a public one. As we've explained, messages are encrypted with a public key (which can be distributed with the world safely) and decrypted using the corresponding private key (which must be kept highly protected).

As we saw in Chapter 7, Introduction...